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Abstract:

A laminated film includes a resin layer provided on at least one surface
of a thermoplastic resin film substrate, wherein the resin layer
comprises an acrylic-modified polyester whose acrylic resin component has
a glass-transition temperature of not lower than 67° C. and a
sugar alcohol and/or a sugar alcohol derivative; the mass ratio of the
acrylic-modified polyester to the sugar alcohol and the sugar alcohol
derivative (the mass of the acrylic-modified polyester/the total mass of
the sugar alcohol and the sugar alcohol derivative) is from 75/25 to
97/3; the total content of the acrylic-modified polyester and the sugar
alcohol and sugar alcohol derivative is 65% by mass or more based on the
total resin layer; and the haze value of the laminated film is not more
than 2.0%.

Claims:

1. A laminated film comprising a resin layer provided on at least one
surface of a thermoplastic resin film substrate, wherein the resin layer
comprises an acrylic-modified polyester whose acrylic resin component has
a glass-transition temperature of not lower than 67.degree. C. and a
sugar alcohol and/or a sugar alcohol derivative; a mass ratio of the
acrylic-modified polyester to the sugar alcohol and the sugar alcohol
derivative (mass of the acrylic-modified polyester/total mass of the
sugar alcohol and the sugar alcohol derivative) is from 75/25 to 97/3;
total content of the acrylic-modified polyester, the sugar alcohol, and
the sugar alcohol derivative is 65% by mass or more based on the total
resin layer; and haze value of the laminated film is not more than 2.0%.

2. The laminated film according to claim 1, wherein the glass-transition
temperature of the acrylic resin component in said acrylic-modified
polyester is 93.degree. C. or higher.

3. The laminated film according to claim 1, wherein the mass ratio of the
acrylic resin component to the polyester resin component in said
acrylic-modified polyester (the mass of the acrylic resin component/the
mass of the polyester resin component) is from 30/70 to 90/10, and the
acrylic resin component contain alkyl methacrylate and/or alkyl acrylate
in an amount from 50% by mass to 97% by mass based on the total acrylic
resin component and epoxy-containing acrylic monomer in an amount from 3%
by mass to 50% by mass based on the total acrylic resin component.

4. The laminated film according to claim 1, wherein said resin layer
comprises inorganic particles, and taking thickness of the resin layer as
d, a highest peak among the peaks in particle-size distribution of the
inorganic particles is in a range of particle size 1.05 d to 4.50 d.

5. The laminated film according to claim 4, wherein at least one peak
other than the highest peak among the peaks in particle-size distribution
of said inorganic particles is in a range of particle size 1.05 d to 4.50
d.

6. The laminated film according to claim 1, wherein said resin layer
comprises a fluorochemical surfactant.

7. The laminated film according to claim 1, wherein said acrylic-modified
polyester is cross-linked by at least one compound (C) selected from the
group consisting of an oxazoline-based compound, a carbodiimide-based
compound, an epoxy-based compound, and a melamine-based compound.

8. A method of producing a laminated film comprising: applying a resin
composition onto at least one surface of a thermoplastic resin film
before completion of crystal orientation, followed by drying; drawing
said thermoplastic resin film at least in an axial direction; and then
subjecting said thermoplastic resin film to a heat treatment to complete
crystal orientation of the thermoplastic resin film, wherein said resin
composition comprises an acrylic-modified polyester whose acrylic resin
component has a glass-transition temperature of not lower than 67.degree.
C. and a sugar alcohol and/or derivative thereof; mass ratio of the
acrylic-modified polyester to the sugar alcohol and the sugar alcohol
derivative (mass of the acrylic-modified polyester/total mass of the
sugar alcohol and the sugar alcohol derivative) is from 75/25 to 97/3;
and total content of the acrylic-modified polyester, the sugar alcohol,
and the sugar alcohol derivative is 65% by mass or more based on the
solid content of the resin composition, and said heat treatment
temperature is a temperature lower than the boiling points of said sugar
alcohol and said sugar alcohol derivative.

9. The method according to claim 8, wherein said resin composition
comprises a fluorochemical surfactant in an amount from 0.01% by mass to
0.3% by mass based on the total resin composition.

10. The laminated film according to claim 2, wherein the mass ratio of
the acrylic resin component to the polyester resin component in said
acrylic-modified polyester (the mass of the acrylic resin component/the
mass of the polyester resin component) is from 30/70 to 90/10, and the
acrylic resin component contain alkyl methacrylate and/or alkyl acrylate
in an amount from 50% by mass to 97% by mass based on the total acrylic
resin component and epoxy-containing acrylic monomer in an amount from 3%
by mass to 50% by mass based on the total acrylic resin component.

11. The laminated film according to claim 2, wherein said resin layer
comprises inorganic particles, and taking thickness of the resin layer as
d, a highest peak among the peaks in particle-size distribution of the
inorganic particles is in a range of particle size 1.05 d to 4.50 d.

12. The laminated film according to claim 3, wherein said resin layer
comprises inorganic particles, and taking thickness of the resin layer as
d, a highest peak among the peaks in particle-size distribution of the
inorganic particles is in a range of particle size 1.05 d to 4.50 d.

13. The laminated film according to claim 2, wherein said resin layer
comprises a fluorochemical surfactant.

14. The laminated film according to claim 3, wherein said resin layer
comprises a fluorochemical surfactant.

15. The laminated film according to claim 4, wherein said resin layer
comprises a fluorochemical surfactant.

16. The laminated film according to claim 5, wherein said resin layer
comprises a fluorochemical surfactant.

Description:

RELATED APPLICATIONS

[0001] This is a §371 of International Application No.
PCT/JP2011/054684, with an international filing date of Mar. 2, 2011 (WO
2011/122209 A1, published Oct. 6, 2011), which is based on Japanese
Patent Application No. 2010-256623, filed Nov. 17, 2010 and Japanese
Patent Application No. 2010-077059, filed Mar. 30, 2010, the subject
matter of which are incorporated by reference.

TECHNICAL FIELD

[0002] This disclosure relates to a laminated film in which a resin layer
is laminated on a thermoplastic resin film, and more particularly to a
laminated film having a resin layer that is excellent in inhibition of
oligomers that precipitate from a thermoplastic resin film upon heat
treatment.

BACKGROUND

[0003] Thermoplastic resin films, particularly biaxially drawn polyester
films, have excellent properties such as mechanical properties,
electrical properties, dimensional stability, transparency, and chemical
resistance, and therefore have been widely used as a substrate film in a
number of applications such as magnetic recording materials and packaging
materials. Especially in recent years, they are in increasing demand as
various optical films including display materials related to flat-panel
display. In such a flat-panel display, a plurality of optical films
having various functions are laminated for use in most cases. Therefore,
methods for providing a polyester film surface with adhesion property
have hitherto been studied. In particular, formation of an adhesion resin
layer by coating provides adhesion to various materials.

[0004] However, there have been cases where, although adhesion property to
various resins has been obtained, for example, heat treatment in
processing has caused precipitation of oligomers from a thermoplastic
resin film, resulting in unsuitability for practical use as an end
product due to whitening or film surface contamination. Therefore,
laminating a coating film on a resin film surface in order to inhibit
oligomers has hitherto been studied. For example, the method of providing
a coating film using an acrylic-modified polyester Japanese Patent
Publication Nos, 04-263937 A, 2003-012841 A and 2002-011841 A, the method
of adding an additive such as a resin having a particular functional
group, mineral oil, or a cross-linker to a resin layer Japanese Patent
Publication Nos. 2006-281498 A and 2002-127621 A, and the method of
providing adhesion property and heat resistance property by laminating a
coating film comprising various binder resins and a cross-linker using
the in-line coating method in which application is carried out during the
process of producing a thermoplastic resin film Japanese Patent
Publication Nos. 2010-143202 A, 2006-321165 A and 2008-179148 Δ
have been proposed.

[0005] However, according to the method of providing an acrylic-modified
polyester on a film surface as a resin layer as described in Japanese
Patent Publication Nos. 04-263937 A, 2003-012841 A and 2002-011841 A,
although the acrylic-modified polyester contains an acrylic component
having a glass-transition temperature of not less than a certain
temperature, defects and cracks occur in the resin layer when the resin
layer is set, resulting in that sufficient oligomer-inhibiting effect
cannot be obtained, and besides the transparency of a laminated film can
be impaired. In particular, when providing an acrylic resin having a
glass-transition temperature of more than 90° C. as a resin layer
as described in Japanese Patent Publication Nos. 2010-143202 A,
2006-321165 A and 2008-179148 A, cracks occur in the resin layer during
film formation, and therefore haze can increase to significantly decrease
homogeneous film-formation. Further, according to the method using an
additive such as mineral oil or a cross-linker as described in Japanese
Patent Publication Nos. 2006-281498 A and 2002-127621 A, the additive
itself can bleed out on a surface layer of a resin layer during the resin
layer formation or over time after the film formation, causing, for
example, whitening of the resin film and film surface contamination as
well as oligomer precipitation.

[0006] Thus, it could be helpful to provide a resin film having an
excellent transparency and inhibition of oligomer.

SUMMARY

[0007] We thus provide:

[0008] A laminated film comprising a resin layer provided on at least one
surface of a thermoplastic resin film substrate, wherein

[0009] the resin layer comprises an acrylic-modified polyester whose
acrylic resin component has a glass-transition temperature of not lower
than 67° C. and a sugar alcohol and/or a sugar alcohol derivative;

[0010] the mass ratio of the acrylic-modified polyester to the sugar
alcohol and the sugar alcohol derivative (the mass of the
acrylic-modified polyester/the total mass of the sugar alcohol and the
sugar alcohol derivative) is from 75/25 to 97/3;

[0011] the total content of the acrylic-modified polyester and the sugar
alcohol and sugar alcohol derivative is 65% by mass or more based on the
total resin layer; and

[0012] the haze value of the laminated film is not more than 2.0%.

[0013] The laminated film has not only excellent initial transparency, but
also excellent inhibition of oligomer particularly after heat treatment
and has a transparency-maintaining effect.

DETAILED DESCRIPTION

[0014] Our laminated film will now be described in detail.

[0015] We provide a laminated film in which a resin layer is laminated on
at least one surface of a thermoplastic resin film as a substrate film,
and the resin layer comprises an acrylic-modified polyester (A) whose
acrylic resin component has a glass-transition temperature of not lower
than 67° C. and a sugar alcohol (B1) and/or a sugar alcohol
derivative (B2). If necessary, inorganic particles (D) and at least one
compound (C) selected from the group consisting of an oxazoline-based
compound, a carbodiimide-based compound, an epoxy-based compound, and a
melamine-based compound can be used, and besides various additives such
as slip agents and surfactants can be used to the extent that
transparency and inhibition of oligomer are not impaired.

[0016] It is necessary that the laminated film have a haze of not more
than 2.0%, and more preferably not more than 1.0%. If the haze is not
more than 2.0%, when the laminated film is used as an optical film for,
for example, display, for example, cloudiness of display can be
prevented, and decrease in resolution can be prevented. Further, the
laminated film can also be used as a transparent adhesion film that
requires other thermal processing, and its use can be expanded also for
versatile use.

[0017] The haze of not more than 2.0% can be achieved by controlling the
ratio of the content of the acrylic-modified polyester (A) to the total
content of the sugar alcohol (B1) and the sugar alcohol derivative (B2)
in the resin layer above a certain value to thereby improve homogeneous
film-formation of the acrylic-modified polyester in the resin layer and
prevent crack generation. The details will be described below.

[0018] (1) Acrylic-Modified Polyester (A)

[0019] The acrylic-modified polyester (A) is one in which an acrylic resin
component and a polyester resin component are mixed with and/or bound to
each other and encompasses, for example, graft-type one and block-type
one. Either of the acrylic resin component and the polyester resin
component in the acrylic-modified polyester (A) may have a higher degree
of copolymerization.

[0020] The acrylic-modified polyester resin (A) can be produced, for
example, by adding a radical initiator to both ends of a polyester to
allow polymerization of acrylic monomers, adding a radical initiator to
side chains of a polyester to allow polymerization of acrylic monomers,
or attaching hydroxyl groups to side chains of an acrylic resin to allow
reaction with a polyester having an isocyanate group or a carboxyl group
at its terminus.

[0021] The glass-transition temperature of the acrylic resin component of
the acrylic-modified polyester (A) (hereinafter referred to as "Tg" for
short) needs to be not lower than 67° C. and is preferably
90° C. or higher, more preferably 93° C. or higher, and
particularly preferably 97° C. When Tg is not lower than
67° C., thermal molecular mobility of the acrylic resin component
is inhibited, enhancing the effect of inhibiting oligomers that
precipitates from the thermoplastic resin film as a substrate from
exiting the laminated film. Further, the effect of oligomer inhibition
can be ensured, and besides the bleed-out of the components contained in
the resin layer and the blocking phenomenon where resin layers adhere to
each other can be inhibited.

[0022] The acrylic resin component in the acrylic-modified polyester (A)
preferably has a Tg of 90° C. or higher, more preferably
93° C. or higher, and particularly preferably 97° C. or
higher. When the Tg is 90° C. or higher, the hardness of the resin
layer can be further enhanced to form a strong resin layer, which
prevents exposure of the thermoplastic film on the surface due to
abrasion or flaws of the resin layer, whereby the effect of oligomer
inhibition can be more stably maintained. The Tg of the acrylic resin
component is preferably not higher than 135° C. When the Tg of the
acrylic resin component is higher than 135° C., cracks can occur
in the resin layer during film formation. As a result, the haze can be
more than 2.0%, and the effect of oligomer inhibition can be reduced.

[0023] The Tg of the acrylic resin component can be calculated by
substituting the Tg of single polymers (mass average molecular weight:
not less than 2000) of each of the alkyl methacrylate, alkyl acrylate,
and epoxy-containing acrylic monomer described below into known Fox's
approximation (1).

1/Tg=W1/Tg1+W2/Tg2 . . . +Wn/Tgn (1)

[0024] wherein

[0025] Tg: Tg of copolymer (K)

[0026] Tg1, Tg2, Tgn: Tg of single polymers of each acrylic
component (K)

[0028] The mass ratio of the acrylic resin component to the polyester
resin component (the mass of the acrylic resin component/the mass of the
polyester resin component) in the acrylic-modified polyester (A) is
preferably from 30/70 to 90/10. The lower limit of the mass ratio is more
preferably 40/60 or more. The upper limit of the mass ratio is more
preferably 70/30 or less. When the mass ratio of the acrylic resin
component to the polyester resin component is from 30/70 to 90/10, the
oligomer-inhibiting effect due to the acrylic resin component can be
ensured, resulting in good resin layer formation by the polyester resin
and good adhesion property of the resin layer to the thermoplastic resin
film.

[0029] The acrylic resin component constituting the acrylic-modified
polyester (A) preferably contains alkyl methacrylate and/or alkyl
acrylate in an amount from 50% by mass to 97% by mass based on the total
acrylic resin component and epoxy-containing acrylic monomer in an amount
from 3% by mass to 50% by mass based on the total acrylic resin
component. The content of alkyl methacrylate and/or alkyl acrylate is
more preferably from 80% by mass to 95% by mass based on the total
acrylic resin component. The content of the epoxy-containing acrylic
monomer is more preferably from 5% by mass to 20% by mass based on the
total acrylic resin component. "The content of alkyl methacrylate and/or
alkyl acrylate" refers to the content of alkyl methacrylate when the
acrylic-modified polyester (A) does not contain alkyl methacrylate; it
refers to the content of alkyl acrylate when the acrylic-modified
polyester (A) does not contain alkyl acrylate; and it refers to the total
content of both when the acrylic-modified polyester (A) comprises both of
alkyl methacrylate and alkyl acrylate.

[0030] When alkyl methacrylate and/or alkyl acrylate are contained in an
amount of not less than 50% by mass based on the total acrylic resin
component, the acrylic-modified polyester is readily polymerized, and
when contained in an amount of not more than 97% by mass, the effect of
epoxy-containing acrylic monomer described below can be ensured. When
epoxy-containing acrylic monomer is contained in an amount of not less
than 3% by mass based on the total acrylic resin component, the crosslink
density of the acrylic resin component is maintained, whereby wear of the
resin layer and thermal deformation of the resin layer during thermal
processing can be prevented, and when contained in an amount of not more
than 50% by mass, the effect of alkyl methacrylate and/or alkyl acrylate
described above can be ensured.

[0032] Preferred examples of the epoxy group-containing acrylic monomer
include glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl
ether. These may be used alone or in combination of two or more.

[0033] The polyester resin component constituting the acrylic-modified
polyester is one having an ester bond on the main chain or side chain and
is composed of a dicarboxylic acid component and a diol component. As a
carboxylic acid component constituting the polyester resin, an aromatic,
aliphatic, or alicyclic dicarboxylic acid and tri- or more polycarboxylic
acid can be used. As an aromatic dicarboxylic acid, terephthalic acid,
isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethyl
terephthalic acid, 5-sodium sulfoisophthalic acid, 1,4-naphthalene
dicarboxylic acid, and the like, and ester-forming derivatives thereof
can be used.

[0034] As a glycol component of the polyester resin, ethylene glycol,
diethylene glycol, polyethylene glycol, propylene glycol, polypropylene
glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl
glycol, and the like can be used.

[0035] In cases where the polyester resin component is dissolved or
dispersed in an aqueous solvent to be used as an aqueous resin
composition, it is preferable to copolymerize a compound comprising a
sulfonate group and a compound comprising a carboxylate group in order to
facilitate water solubilization or water dispersion of the polyester
resin component.

[0037] Examples of the compound comprising a sulfonate group that can be
used include, for example, sulfo-terephthalic acid, 5-sulfoisophthalic
acid, 5-sodium sulfoisophthalic acid, and 4-sulfoisophthalic acid, or
alkali metal salts, alkaline earth metal salts, and ammonium salts
thereof, but are not limited thereto.

[0038] The acrylic-modified polyester used in the resin layer can be
produced by the following production method. First, a polyester resin
component is produced as described below. For example, it can be
produced, for example, by directly bringing a dicarboxylic acid component
and a glycol component into esterification reaction, or by the production
method comprising the first step of bringing a dicarboxylic acid
component and a glycol component into transesterification reaction and
the second step of bringing the reaction product of the first step into
polycondensation reaction. In this method, for example, alkali metal,
alkaline earth metal, manganese, cobalt, zinc, antimony, germanium,
titanium compound, and the like can be used as a reaction catalyst.

[0039] Next, the polyester resin component is dispersed in a solvent, and
for dispersion particularly in an aqueous solvent, the polyester resin is
dissolved or dispersed under stirring in an aqueous solution of an
alkaline compound such as aqueous ammonia, sodium hydroxide, potassium
hydroxide, various amines, or the like. In this case, water-soluble
organic solvents such as methanol, ethanol, isopropanol, butyl
cellosolve, and ethyl cellosolve may be used in combination.

[0040] Then, to produce an acrylic-modified polyester, a polymerization
initiator and, if necessary, an emulsifying dispersant and the like are
added into a dispersion of the polyester resin component, and an acrylic
resin component is slowly added at a constant temperature, after which
the resultant is allowed to react for several hours to thereby produce a
dispersion of the acrylic-modified polyester. The dispersion obtained is
a mixture of an acrylic-modified polyester, a polyester resin component,
and an acrylic resin component.

[0041] The polymerization initiator is not particularly limited, and a
common radical polymerization initiator, for example, water-soluble
peroxide such as potassium persulfate, ammonium persulfate, or hydrogen
peroxide; oil-soluble peroxide such as benzoyl peroxide or t-butyl
hydroperoxide; or an azo compound such as azodiisobutyronitrile can be
used.

[0042] (2) Sugar Alcohol (B1), Sugar Alcohol Derivative (B2)

[0043] The sugar is a general term of carbohydrates having three or more
carbon atoms represented by the molecular formula CmHnOp (m, n, and p:
integer of 3 or more; and n: p×2) and those having in their
molecule a carbonyl group(s) such as an aldehyde group(s) or a ketone
group(s). The sugar alcohol is an alcohol having one or more hydroxyl
groups obtained by reducing the carbonyl group of a sugar molecule. For a
sugar molecule having two or more carbonyl groups, as long as at least
one or more carbonyl groups are reduced and the molecule has one or more
hydroxyl groups, it shall be the sugar alcohol even though the other
carbonyl groups remain unreduced.

[0044] A sugar alcohol derivative refers to a compound in which a portion
of hydroxyl groups is in the form of a salt or a compound in which a
portion of hydroxyl groups has reacted with other functional groups in a
sugar alcohol having two or more hydroxyl groups, provided that it is
necessary to have at least one or more hydroxyl groups.

[0045] Although the sugar alcohol and the sugar alcohol derivative is not
particularly restricted to be of chain structure or of cyclic structure,
it is preferably one having a boiling point as a simple substance of
170° C. or higher. By using one having a boiling point as a simple
substance of 170° C. or higher, homogeneous film-formation of an
acrylic-modified polyester in a resin layer can be improved in the
process of forming the resin layer on a laminated film, which prevents
crack generation to thereby suppress the increase of a haze value. They
are stably present in the resin layer not only when drying a solvent in a
resin composition and during heat treatment to complete crystal
orientation of a thermoplastic resin film but also stably present in the
resin layer despite the change over time after forming the resin layer
and the heat treatment, and can express the oligomer-inhibiting effect.
Specific examples of the sugar alcohol include glycerin, erythritol,
threitol, arabinitol, xylitol, ribitol, iditol, galactitol, glucitol,
mannitol, volemitol, perseitol, and inositol. Examples of the sugar
alcohol derivative include derivatives of these sugar alcohols. These may
be used alone, or a mixture of two or more thereof may be used. Among
them, glycerin, xylitol, glucitol, mannitol, and erythritol are suitable
because of its industrial availability.

[0047] The mass ratio of the acrylic-modified polyester (A) to the sugar
alcohol (B1) and sugar alcohol derivative (B2) contained in the resin
layer (the mass of A/the total mass of B1 and B2; hereinafter referred to
as (A/(B1+B2))) is in the range of 75/25 to 97/3. The lower limit of the
mass ratio is preferably 85/15 or more and more preferably 90/10 or more.
The upper limit of the mass ratio is preferably 95/5 or less and more
preferably 93/7 or less. Although described as "the sugar alcohol (B1)
and sugar alcohol derivative (B2)", this does not mean that both of the
sugar alcohol (B1) and the sugar alcohol derivative (B2) are necessarily
contained in the resin layer. Also, in the case where the sugar alcohol
(B1) is not contained as well as in the case where the sugar alcohol
derivative (B2) is not contained in the resin layer, such a description
is used. When the ratio of the acrylic-modified polyester (A) is not less
than 0.75, a stable and uniform resin layer can be formed on a
thermoplastic resin film, and besides the desired oligomer-inhibiting
effect can be sufficiently expressed. When the ratio of the total of the
sugar alcohol (B1) and sugar alcohol derivative (B2) is not less than
0.03, evaporation of a solvent during resin layer formation and crack
generation of the acrylic-modified polyester (A) caused by heat treatment
described below can be prevented. Particularly in the in-line coating
method described below, cracks in the resin layer that occur during the
drawing process of a thermoplastic resin film are prevented, whereby a
stable and uniform resin layer can be formed on the thermoplastic resin
film, and the haze of the laminated film can be no more than 2.0%;
besides the desired oligomer-inhibiting effect can be sufficiently
expressed.

[0048] The total content of the acrylic-modified polyester (A) and the
sugar alcohol (B1) and sugar alcohol derivative (B2) is 65% by mass or
more, more preferably 75% by mass or more, and more preferably 90% by
mass or more, based on the total resin layer. Although described as "the
total content of the acrylic-modified polyester (A) and the sugar alcohol
(B1) and sugar alcohol derivative (B2)", this does not mean that both of
the sugar alcohol (B1) and the sugar alcohol derivative (B2) are
necessarily contained in the resin layer. Also, in the case where the
sugar alcohol (B1) is not contained as well as in the case where the
sugar alcohol derivative (B2) is not contained in the resin layer, such a
description is used. When the content is 65% by mass or more based on the
total resin layer, the desired oligomer-inhibiting effect due to the
acrylic-modified polyester (A) and the sugar alcohol (B1) and sugar
alcohol derivative (B2) can be expressed.

[0049] (4) Inorganic Particles (D)

[0050] Preferred examples of the inorganic particles include silica,
colloidal silica, alumina, kaolin, talc, mica, calcium carbonate, barium
sulfate, carbon black, zeolite, titanium oxide, fine particles composed
of various metals or oxides thereof, and the like. Silica, colloidal
silica, and alumina are preferred particularly in terms of high hardness
and heat resistance property. By using inorganic particles, smoothness of
the resin layer can be improved to prevent the degradation of the resin
layer due to the friction between resin layers, and the
oligomer-inhibiting effect can be maintained; besides, at the pressure
test described below or when laminated films such as a laminated film
stored in the form of a roll are laminated on each other and pressure is
put thereon, the resin layer can be protected from deformation and
rupture due to the pressure, and the effect of inhibiting oligomers from
the resin layer after the pressurization can be maintained.

[0051] The number average particle size of the inorganic particles
contained in the resin layer is determined by the peak position in a
graph of particle size distribution (graph of frequency distribution)
that represents the frequency of the particle size of the inorganic
particles contained in the resin layer. Even if inorganic particle groups
having a different number-average particle size are contained in the
resin layer, the value of each number-average particle size can be
determined by the peak position in a graph of particle size distribution.
Taking the thickness of the resin layer as d, the highest frequency
distribution peak (hereinafter referred to as the first peak) among the
peaks in the particle-size distribution of inorganic particles is
preferably in the range of particle size 1.05 d to 4.50 d. In other
words, the number-average particle size of the inorganic particle group
having the most particle number among the inorganic particle groups
having a different number-average particle size contained in the resin
layer is preferably in the range of particle size 1.05 d to 4.50 d. The
lower limit of the first peak position is more preferably 2.00 d or more.
The upper limit of the first peak position is more preferably 4.00 d or
less. The method of measuring resin layer thickness d and particle-size
distribution will be described below. When the first peak position is not
less than 1.05 d, inorganic particles protrude from a resin layer
surface, whereby a space is provided between laminated films when the
laminated films are in the form of a roll or laminated on each other. As
a result, deformation and rupture of the resin layer due to the pressure
can be prevented, and an excellent oligomer-inhibiting effect can be
maintained. When the first peak position is not more than 4.50 d, falling
off of the inorganic particles from the resin layer can be prevented.

[0052] Further, at least one of the frequency distribution peaks other
than the first peak (hereinafter referred to as other peaks) is
preferably in the range of particle size 1.05 d to 4.50 d. In other
words, the number-average particle size of at least one inorganic
particle group other than the inorganic particle group having the most
particle number among the inorganic particle groups having a different
number-average particle size contained in the resin layer is preferably
in the range of particle size 1.05 d to 4.50 d. The lower limit of the
other peak position is more preferably 2.00 d or more. The upper limit of
the other peak position is more preferably 4.00 d or less. When the other
peaks are also in the range of particle size 1.05 d to 4.50 d, even if
pressure is applied locally to the space between laminated films provided
by the inorganic particle group having the most particle number, other
inorganic particle groups supportingly maintain the space, and direct
contact between the laminated films can be prevented.

[0053] Other peaks in the range of particle size 1.05 d to 4.50 d are
preferably the second highest frequency distribution peak among the peaks
in the particle-size distribution. In other words, the number-average
particle size of the inorganic particle group having the second most
particle number among the inorganic particle groups having a different
number-average particle size contained in the resin layer is preferably
in the range of particle size 1.05 d to 4.50 d. The protrusion of the
inorganic particle group having the second most particle number from the
resin layer allows the most effective support to the space between
laminated films when pressure is applied locally as mentioned above.

[0054] In the case where a plurality of peaks having the same peak height
of the particle-size distribution of inorganic particles is present,
peaks are numbered in order of decreasing particle size. This is because
the effect of smoothness and pressure resistance is exerted
preferentially on larger particles against friction arising between
laminated films and pressure. Specifically, for example, in the case
where two highest peaks are present, one having larger particle size is
the first peak, and one having smaller particle size is the second peak.
For example, in the case where two second highest peaks are present, one
having larger particle size is the second peak, and one having smaller
particle size is the third peak.

[0055] The total mass of the inorganic particles contained in the resin
layer is preferably from 0.2% by mass to 4.0% by mass based on the total
mass of the resin layer. The lower limit of the content of the inorganic
particles is more preferably 1.0% by mass or more. The upper limit the
content of the inorganic particles is more preferably 3.0% by mass or
less. When the content is not less than 0.2% by mass, uniform space can
be provided between laminated films when the laminated film are in the
form of a roll or laminated on each other. When the content is not more
than 4.0% by mass, the haze value of the laminated film can be no more
than 2.0%.

[0056] (5) Fluorochemical Surfactant (E)

[0057] The fluorochemical surfactant is not particularly limited as long
as it comprises at least one molecule having a fluorocarbon chain, which
is obtained by substituting fluorine atoms for hydrogen atoms in the
alkyl chain in a molecule, and a static surface tension of not more than
40 mN/m. As such a fluorochemical surfactant, sulfonate, carboxylate, and
ethylene oxide adduct having a perfluoroalkyl chain are preferred in
terms of surface tension-reducing capability and a leveling effect
produced when a resin composition is applied, and, specifically, for
example, those having a C9F17O-group or a
C6F11O-group at both terminals or those having them at one
terminal represented by
α-perfluorononenyloxy-ω-perfluorononelylpolyethylene oxide
and α-perfluorononenyloxy-ω-methyl polyethylene oxide are
preferred. By using a fluorochemical surfactant, at the pressure test
described below or when laminated films such as laminated films stored in
the form of a roll are laminated on each other and pressure is put
thereon, still better oligomer-inhibiting ability can be maintained with
respect to the oligomer-inhibiting effect of inorganic particles. The
mechanism of the effect of a fluorochemical surfactant on pressure,
although not clearly known, is presumably due to (i) to (iii) below.

(i) The high surface tension-reducing effect of a fluorochemical
surfactant improves the leveling property of a resin layer, and particle
parts protruding from the resin layer appear more clearly from the resin
layer surface. As a result, a space between laminated films is more
clearly formed when the laminated films are in the form of a roll or
laminated on each other. (ii) Inorganic particles and a binder resin of a
resin layer have a different surface energy. Therefore, a gap is formed
between the inorganic particles and the binder resin, and oligomers can
precipitate from the gap. By adding a fluorine surfactant, repulsive
force between the inorganic particles and the binder resin is reduced,
and the gap becomes smaller, whereby precipitation of oligomers can be
inhibited. (iii) A fluorocarbon chain is rigid and inflexible and easily
arranged on a resin layer surface, and therefore it is able to exert
excellent resistance to pressure to enhance the hardness on the resin
layer surface.

[0058] The content of the fluorochemical surfactant is preferably from
0.01% by mass to 0.30% by mass based on the total mass of the resin
composition, which is paint that forms a resin layer. The lower limit of
the content is more preferably 0.02% by mass or more. The upper limit of
the content is more preferably 0.20% by mass or less. When the content is
not less than 0.01% by mass, a surface tension-reducing effect can be
exerted on the resin composition. When the content is not more than 0.30%
by mass, excessive precipitation of the surfactant on a surface layer of
the resin layer is prevented when the resin layer is formed, and the haze
value of a laminated film can be no more than 2.0%.

[0059] (6) At Least One Compound (C) Selected from the Group Consisting of
Oxazoline-Based Compound, Carbodiimide-Based Compound, Epoxy-Based
Compound, and Melamine-Based Compound

[0060] In a resin layer, the acrylic-modified polyester (A) is preferably
cross-linked by at least one compound (C) selected from the group
consisting of an oxazoline-based compound, a carbodiimide-based compound,
an epoxy-based compound, and a melamine-based compound.

[0061] Although the oxazoline-based compound is not particularly limited
as long as it has at least one oxazoline group or oxazine group in one
molecule, preferred is a high-molecular compound obtained by polymerizing
addition polymerizable oxazoline group-containing monomers alone or with
other monomers. This is because, by using a high-molecular oxazoline
compound, adhesion property and adhesion property of resistance to moist
heat, for example, to various inks and hard coat agents, flexibility,
toughness, water-resistant property, and solvent resistance as well as
oligomer-inhibiting effect of the resin layer are improved when the resin
layer is provided on a thermoplastic resin film to produce a laminated
film.

[0062] Examples of addition polymerizable oxazoline group-containing
monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline,
2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline,
2-isopropenyl-4-methyl-2-oxazoline, and
2-isopropenyl-5-ethyl-2-oxazoline. These may be used alone, or a mixture
of two or more thereof may be used. Among them, 2-isopropenyl-2-oxazoline
is suitable because of its industrial availability. Other monomers are
not limited as long as they are monomers that are copolymerizable with
addition polymerizable oxazoline group-containing monomers, and examples
thereof include (meth)acrylic acid esters such as alkyl acrylate and
alkyl methacrylate (examples of alkyl groups include methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, and
cyclohexyl); unsaturated carboxylic acids such as acrylic acid, methacryl
acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene
sulfonic acid, and salts thereof (for example, sodium salt, potassium
salt, ammonium salt, and tertiary amine salt); unsaturated nitriles such
as acrylonitrile and methacrylonitrile; unsaturated amides such as
acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide,
N,N-dialkylacrylamide, N,N-dialkyl methacrylate (examples of alkyl groups
include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl,
2-ethylhexyl, and cyclohexyl); vinyl esters such as vinyl acetate, vinyl
propionate, and those obtained by adding polyalkylene oxide to an ester
moiety of acrylic acid or methacryl acid; vinyl ethers such as methyl
vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and
propylene; halogen-containing α,β-unsaturated monomers such as
vinyl chloride, vinylidene chloride, and vinyl fluoride;
α,β-unsaturated aromatic monomers such as styrene and
α-methylstyrene; and the like. These monomers may be used alone or
in combination of two or more.

[0063] Although the carbodiimide-based compound is not particularly
limited as long as it has, for example, at least one carbodiimide
structure represented by general formula (2) below in one molecule,
particularly preferred is a polycarbodiimide compound having two or more
in one molecule in terms, for example, of adhesion property of resistance
to moist heat. In particular, a high-molecular isocyanate-based compound
having a plurality of carbodiimide groups at the terminals or in a side
chain of a polymer such as a polyester resin and an acrylic resin can be
preferably used, because adhesion property and adhesion property of
resistance to moist heat, for example, to various inks and hard coat
agents, flexibility, and toughness as well as oligomer-inhibiting effect
of the resin layer are improved when the resin layer is provided on a
thermoplastic resin film to produce a laminated film.

--N═C═N-- (2)

[0064] A carbodiimide-based compound can be produced by applying known
techniques and is generally obtained by polycondensation of a
diisocyanate-based compound in the presence of a catalyst. As a
diisocyanate-based compound, which is a starting material of a
polycarbodiimide compound, aromatic, aliphatic, alicyclic diisocyanate,
and the like can be used, and, specifically, tolylene diisocyanate,
xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene
diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate,
dicyclohexyl diisocyanate, and the like can be used. Further, to improve
the water solubility and water dispersibility of the polycarbodiimide
compound, a surfactant may be added, or a hydrophilic monomer such as
polyalkylene oxide, a quaternary ammonium salt of dialkylamino alcohol,
and hydroxyalkyl sulfonate may be added or used without eliminating the
effects of this disclosure.

[0065] The epoxy-based compound is not particularly limited as long as it
has at least one or more epoxy groups in one molecule, and a monoepoxy
compound, a diepoxy compound, a polyepoxy compound, a modified epoxy
compound, and the like can be used. In particular, a bi- or more
functional epoxy-based compound is preferably used, and it can preferably
be used because adhesion property and adhesion property of resistance to
moist heat, for example, to various inks and hard coat agents, toughness,
water-resistant property, and solvent resistance as well as
oligomer-inhibiting effect of the resin layer are improved when the resin
layer is provided on a thermoplastic resin film to produce a laminated
film. As an epoxy-based compound, specifically, for example, sorbitol
polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol
polyglycidyl ether, polyethylene glycol diglycidyl ether, fatty
acid-modified glycidyl, glycidyl ether, glycidyl methacrylate, and the
like can be used.

[0066] As a melamine-based compound, although this is not a limited
example, a compound that has been etherified by dehydration condensation
reaction of a methylol melamine derivative obtained by condensation of
melamine with formaldehyde and a lower alcohol such as methyl alcohol,
ethyl alcohol, or isopropyl alcohol is preferred in terms of
hydrophilization, and it can be preferably used because adhesion property
and adhesion property of resistance to moist heat, for example, to
various inks and hard coat agents, flexibility, toughness, and solvent
resistance as well as oligomer-inhibiting effect of the resin layer are
improved when the resin layer is provided on a thermoplastic resin film
to produce a laminated film. Examples of methylolated melamine
derivatives include monomethylol melamine, dimethylol melamine,
trimethylol melamine, tetramethylol melamine, pentamethylol melamine,
hexamethylol melamine, and the like.

[0067] At least one compound (C) selected from the group consisting of an
oxazoline-based compound, a carbodiimide-based compound, an epoxy-based
compound, and a melamine-based compound (hereinafter referred to as the
compound (C) for short) can be used in any amount as long as the effect
of the acrylic-modified polyester (A), the sugar alcohol (B1), and the
sugar alcohol derivative (B2) is not impaired, but preferably 5 to 50
parts by mass and more preferably 10 to 30 parts by mass, based on 100
parts by mass of the total of the acrylic-modified polyester (A) and the
sugar alcohol (B1) and sugar alcohol derivative (B2). Although described
as "100 parts by mass of the total of the acrylic-modified polyester (A)
and the sugar alcohol (B1) and sugar alcohol derivative (B2)", this does
not mean that both of the sugar alcohol (B1) and the sugar alcohol
derivative (B2) are necessarily contained in the resin layer. Also, in
the case where the sugar alcohol (B1) is not contained as well as in the
case where the sugar alcohol derivative (B2) is not contained in the
resin layer, such a description is used. When the amount is not less than
5 parts by mass, the effect of the compound (C) is expressed, and when
the amount is not more than 50 parts by mass, the effect of the
acrylic-modified polyester (A) and the sugar alcohol (B1) and sugar
alcohol derivative (B2) in the resin layer can be maintained. In addition
to the compound (C), other compounds such as an aziridine compound, an
amide-epoxy compound, a titanate coupling agent such as titanium chelate,
a methylolated or alkylolated urea-based compound, and an
acrylamide-based compound can optionally be used.

[0068] In the resin layer, the acrylic-modified polyester (A) is
preferably cross-linked by the compound (C). Although the mode of
cross-linking is preferably cross-linking reaction between hydrophilic
groups such as carboxylic acid group, hydroxyl group, and amino group of
the acrylic-modified polyester (A) and reactive groups of the compound
(C), it is not necessary that all the hydrophilic groups of the
acrylic-modified polyester (A) be cross-linked to the compound (C): one
portion may react with the moiety other than hydroxyl group of the
acrylic-modified polyester (A); in another portion, one and/or more
compounds (C) may be cross-linked to each other in the resin layer; and
in the other portion, the compound (C) may be present without
cross-linking. If the compound (C) has a cross-linked structure, even if
in part, with the acrylic-modified polyester (A) in the resin layer,
adhesion property and adhesion property of resistance to moist heat,
flexibility, toughness, water-resistant property, solvent resistance, and
the like as well as oligomer-inhibiting effect of the resin layer are
improved, and it can preferably be used.

[0069] (7) Thermoplastic Resin Film

[0070] In the laminated film, the thermoplastic resin film used as a
substrate film is a general term of films that are obtained by using a
thermoplastic resin and melt or soften by heat. Examples of the
thermoplastic resin include polyester resins, polyolefin resins such as
polypropylene resins and polyethylene films, polylactic acid resins,
polycarbonate resins, acrylic resins such as polymethacrylate resins and
polystyrene resins, polyamide resins such as nylon resins, polyvinyl
chloride resins, polyurethane resins, fluororesins, polyphenylene resins,
and the like. The thermoplastic resin used in the thermoplastic resin
film may be a monopolymer or copolymer. Further, a plurality of resins
may be used.

[0072] The resin layer, considering that it has a high effect of oligomer
inhibition, is preferably applied to a thermoplastic resin film prone to
oligomer generation. In view of this, polyester films or polyethylene
films are preferred as a substrate film. In particular, polyester films
having also mechanical strength and versatility are preferred.

[0073] Thus, the polyester resin constituting a polyester film
particularly suitably used as a thermoplastic resin film will now be
described in detail.

[0074] First, polyester is a general term of polymers having ester bonds
as a main bonding chain of the main chain, and those having as a main
component at least one component selected from ethylene terephthalate,
propylene terephthalate, ethylene-2,6-naphthalate, butylene
terephthalate, propylene-2,6-naphthalate,
ethylene-4-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate, and the like
can preferably be used. Polyethylene terephthalate is preferably used as
a thermoplastic resin used in the thermoplastic resin film. In the case
where heat or shrinkage stress acts on the thermoplastic resin film,
polyethylene-2,6-naphthalate, which has excellent heat resistance
property and rigidity, is particularly preferred.

[0075] A polyester film using the above-described polyester is preferably
one that is biaxially oriented. A biaxially oriented polyester film
generally refers to those which are obtained by drawing an undrawn
polyester sheet or film about 2.5- to 5-fold each in the longitudinal
direction and in the width direction perpendicular to the longitudinal
direction, and then applying a heat treatment to complete crystal
orientation, and those which show biaxial orientation pattern in
wide-angle X-ray diffraction. If the thermoplastic resin film is not
biaxially oriented, the thermoplastic resin film will have insufficient
thermal stability, particularly dimensional stability, and mechanical
strength and poor planarity, which is not preferred.

[0076] Further, various additives such as antioxidants, heat stabilizers,
weathering stabilizers, ultraviolet absorbers, organic slip agents,
pigments, dyes, organic or inorganic fine particles, fillers, antistatic
agents, and nucleus formation agents may be added into the thermoplastic
resin film to the extent that the properties thereof are not
deteriorated.

[0077] Although the thickness of the thermoplastic resin film is not
particularly limited and appropriately selected depending on the
application and type, in terms, for example, of mechanical strength and
handleability, it is generally preferably 10 to 500 μm, more
preferably 38 to 250 μm, and most preferably 75 to 150 μm. The
thermoplastic resin film may be a composite film obtained by coextrusion
or may be a film obtained by laminating the obtained films each other by
various methods.

[0078] (8) Method of Forming Resin Layer

[0079] A resin layer can be formed on a thermoplastic resin film by
applying the resin composition containing the acrylic-modified polyester
(A) and the sugar alcohol (B1) and/or sugar alcohol derivative (B2)
described above onto the thermoplastic resin film and drying a solvent as
required. This resin composition is a resin composition comprising an
acrylic-modified polyester (A) whose acrylic resin component has a
glass-transition temperature of not lower than 67° C. and a sugar
alcohol (B1) and/or a sugar alcohol derivative (B2), wherein the mass
ratio of the content of the acrylic-modified polyester (A) to the total
content of the sugar alcohol (B1) and sugar alcohol derivative (B2)
(A/(B1+B2)) is from 75/25 to 97/3, and the total content of the
acrylic-modified polyester (A) and the sugar alcohol (B1) and sugar
alcohol derivative (B2) based on the solid content of the resin
composition is 65% by mass or more.

[0080] An aqueous solvent (F) is preferably used as a solvent. The aqueous
solvent is used not only because it allows the prevention of rapid
evaporation of the solvent during a drying process and formation of a
uniform composition layer but also because it is excellent in terms of
environmental load.

[0081] The aqueous solvent (F) as used herein refers to water or a mixture
of water and a water-soluble organic solvent such as alcohols such as
methanol, ethanol, isopropyl alcohol, and butanol; ketones such as
acetone and methyl ethyl ketone; and glycols such as ethylene glycol,
diethylene glycol, and propylene glycol at any ratio. The aqueous solvent
is used not only because it allows the prevention of rapid evaporation of
the solvent during a drying process and formation of a uniform
composition layer but also because it is excellent in terms of
environmental load.

[0082] As a method of applying the resin composition to the thermoplastic
resin film, either of the in-line coating method or the off coating
method can be used, but the in-line coating method is preferred.

[0083] The in-line coating method is a method in which application is
carried out during the process of producing a thermoplastic resin film.
Specifically, it refers to a method in which application is carried out
at any time during the process in which a thermoplastic resin is
melt-extruded, biaxially drawn, heat-treated, and wound up, and, in
general, the resin composition is applied to any film of an undrawn
(nonoriented) thermoplastic resin film in a substantially amorphous state
obtained by melt extrusion and the following rapid cooling (A film), an
uniaxially drawn (uniaxially oriented) thermoplastic resin film that has
been drawn in the longitudinal direction thereafter (B film), or a
biaxially drawn (biaxially oriented) thermoplastic resin film before heat
treatment that has been drawn further in the width direction (C film).

[0084] It is preferable to employ the method in which a resin composition
is applied to either thermoplastic resin film of the above-described A
film or B film before completion of crystal orientation, and then the
thermoplastic resin film is uniaxially or biaxially drawn and subjected
to a heat treatment at a temperature higher than the boiling point of a
solvent to complete crystal orientation of the thermoplastic resin film
and also provide a resin layer. This method has a merit in production
cost because formation of a thermoplastic resin film and application and
drying of a resin composition (i.e., formation of a resin layer) can be
simultaneously carried out. In addition, it is easy to reduce the
thickness of the resin layer because the drawing is carried out after the
application.

[0085] In particular, the method in which a composition for coating is
applied to the film uniaxially drawn in the longitudinal direction (B
film), which is then drawn in the width direction and subjected to a heat
treatment is excellent. This is because the method involves one less
drawing step than the method in which biaxial drawing is performed after
application to an undrawn film, and therefore defects and cracks of the
resin layer due to the drawing do not readily occur, whereby a
composition layer having an excellent transparency and smoothness can be
formed.

[0086] On the other hand, the off-line coating method is a method in which
a resin composition is applied in a process different from the
film-forming process to a film obtained after the A film described above
has been uniaxially or biaxially drawn and subjected to a heat treatment
to complete the crystal orientation of a thermoplastic resin film or to
the A film.

[0087] The resin layer is preferably provided by the in-line coating
method in terms of the various advantages described above.

[0088] Thus, the best method of forming a resin layer is a method in which
a resin layer is formed by applying a resin composition using the aqueous
solvent (F) onto a thermoplastic resin film using the in-line coating
method and drying the resultant. More preferred is a method in which the
B film after uniaxial drawing is in-line coated with a resin composition.
Further, the solid content concentration of the resin composition is
preferably not more than 10% by mass. When the solid content
concentration is not more than 10% by mass, the resin composition can be
provided with good application properties, and a laminated film provided
with a transparent and uniform composition layer can be produced.

[0090] A resin composition using the aqueous solvent (F) can be prepared
by mixing the acrylic-modified polyester (A) that has been
water-dispersed or water-solubilized as required, an aqueous compound of
the sugar alcohol (B1) and/or sugar alcohol derivative (B2), and the
aqueous solvent (F) in any order at a desired mass ratio and stirring the
resulting mixture. Then, it can be prepared by adding, if necessary, the
compound (C) to the resin composition described above in any order at a
desired mass ratio and stirring the resulting mixture.

[0091] The mixing and stirring can be carried out by shaking a container
by hand, using a magnetic stirrer or a stirring blade, ultrasonic
irradiation, or vibrational dispersion. In addition, various additives
such as slip agents, inorganic particles, organic particles, surfactants,
and antioxidants may be added as required to the extent that the
properties of the resin layer provided by the resin composition are not
deteriorated.

[0092] (10) Application Method

[0093] As a method of applying a resin composition to a thermoplastic
resin film, for example, any known application methods such as the bar
coating method, the reverse coating method, the gravure coating method,
the die coating method, and the blade coating method can be used.

[0094] (11) Heat Treatment

[0095] In the method of producing the laminated film, to complete crystal
orientation of a substrate film and also to complete heat setting of a
resin composition and removal of a solvent to complete formation of a
resin layer, the heat treatment can be carried out in a temperature range
of 160 to 240° C. but needs to be carried out at not higher than
the boiling point of the sugar alcohol (B1) and sugar alcohol derivative
(B2). When the heat treatment is carried out at a temperature of not
lower than 160° C. and not higher than the boiling point of the
sugar alcohol (B1) and sugar alcohol derivative (B2), crystal orientation
of a substrate film can be completed, and besides, during the process of
removing a solvent or with the solvent having been removed, the
acrylic-modified polyester (A) and the sugar alcohol (B1) and sugar
alcohol derivative (B2) can be present as the solid content of the resin
layer in an uniformly mixed state. Further, since the sugar alcohol (B1)
and sugar alcohol derivative (B2) will not boil or evaporate, a resin
layer free from cracks and roughening of the surface caused by the
boiling and evaporation of the sugar alcohol (B1) and sugar alcohol
derivative (B2) can be formed, and therefore the effect of oligomer
inhibition can be expressed.

[0096] (12) Method of Producing Laminated Film

[0097] The method of producing the laminated film will now be described
referring to the case where a polyethylene terephthalate (hereinafter
referred to as PET for short) film is used as a thermoplastic resin film,
but is not limited thereto. First, PET pellets are sufficiently
vacuum-dried, and then the pellets are fed to an extruder and
melt-extruded at about 280° C. into a sheet, which is cooled to
solidify to produce an undrawn (nonoriented) PET film (A film). The film
is drawn 2.5- to 5.0-fold in the longitudinal direction with rollers
heated to 80 to 120° C. to obtain a uniaxially oriented PET film
(B film). The resin composition prepared to have a predetermined
concentration is applied onto one surface of the B film. In this step,
before application, a surface treatment such as a corona discharge
treatment may be carried out on the surface of the PET film to be coated.
Carrying out a surface treatment such as a corona discharge treatment
improves the wettability of the resin composition on the PET film and
prevents the resin composition from being repelled, whereby a uniform
coating thickness can be achieved.

[0098] After the application, the PET film is guided to a heat treatment
zone (preheating zone) at 80 to 130° C. with the ends held by
clips, and the solvent of the resin composition is dried. After the
drying, the PET film is drawn 1.1- to 5.0-fold in the width direction.
The PET film is successively guided to a heat treatment zone (heat
fixation zone) at 160 to 240° C. and subjected to a heat treatment
for 1 to 30 seconds to complete crystal orientation.

[0099] During this heat treatment process (heat fixation process), a
relaxation treatment of 3 to 15% may be carried out in the width
direction or the longitudinal direction as required. The laminated film
thus obtained is a laminated film that is transparent and has an
excellent inhibition of oligomer.

EXAMPLES

Methods of Measuring Properties and Methods of Evaluating Effects

[0100] The method of measuring the properties and methods of evaluating
the effects are as described below.

[0101] (1) Calculation of Glass-Transition Temperature

[0102] The Tg of the acrylic resin component was calculated by
substituting the Tg of single polymers (mass average molecular weight:
not less than 2000) of each of the alkyl methacrylate, alkyl acrylate,
and epoxy-containing acrylic monomer into the copolymer Tg approximation
(1) below.

1/Tg=W1/Tg1+W2/Tg2 . . . +Wn/Tgn (1)

[0103] wherein

[0104] Tg: Tg of copolymer (K)

[0105] Tg1, Tg2, Tgn: Tg of single polymers of each acrylic
component (K)

[0108] Total light transmittance and haze were measured using a
turbidimeter "NDH5000" manufactured by NIPPON DENSHOKU INDUSTRIES CO.,
LTD. after a laminated film sample was left to stand for 40 hours in
normalcy (23° C., relative humidity: 50%). Measurement of total
light transmittance and measurement of haze were performed in accordance
with JIS "Test method of total light transmittance of transparent plastic
material" (K7361-1, 1997) and JIS "Method for obtaining haze of
transparent materials" (K7136, 2000), respectively. Three samples of a
square of side 50 mm were prepared. Measurements were made once for each,
three times in total, and the mean value was taken as the haze value of
the sample.

[0109] (3) Heat-Treatment Evaluation

[0110] The laminated film sample used in the measurement of the above
section (2) was fixed at four sides of a metal frame, and the sample
fixed to the metal frame was placed upright against the floor in a
hot-air dryer "HIGH-TEMP-OVEN PHH-200" manufactured by ESPEC CORPORATION.
set at 140° C. (air flow gauge "7"), heated for one hour, and then
left to stand for one hour under air cooling. For the sample from a
thermoplastic resin film on only one surface of which a resin layer is
formed, the thermoplastic resin film's surface opposite to the resin
layer was wiped with an unwoven cloth (HAIZEGAUZE NT-4 available from OZU
CORPORATION.) soaked with acetone, further flushed with acetone, and left
to stand in normalcy for 40 hours for drying. Then the oligomers
precipitated from the thermoplastic resin film's surface opposite to the
resin layer were removed. Thereafter, the sample was measured for the
haze value after heat treatment according to the method of measuring
transmittance/haze described in the above section (2), and the difference
(A) between the haze values at one surface of the resin layer before and
after heat treatment was evaluated as Δ haze value (=(haze value
after heat treatment)-(haze value before heat treatment)). For the sample
from a thermoplastic resin film on both surfaces of which resin layers
are formed, after heating in a hot-air dryer, the sample was left to
stand in normalcy for 40 hours, and then the haze value after heat
treatment was measured according to the method of measuring
transmittance/haze described in the above section (2); the value obtained
by halving (50%) the difference between the haze values before and after
heat treatment was taken as the difference (Δ) of the haze value at
one surface of the resin layer, which was evaluated as Δ haze value
(=((haze value after heat treatment)-(haze value before heat
treatment))/2).

<Δ Haze Value>

[0111] A: Less than 0.3% B: Not less than 0.3% and less than 0.5% C: 0.5%
or more

[0112] In heat-treatment evaluation, "A" is good. When the Δ haze is
less than 0.3%, the change in haze value before and after heat treatment
is visually imperceptible. When the Δ haze is not less than 0.3%
and less than 0.5%, while varying between individuals, the change in haze
value before and after heat treatment can be visually perceptible. When
the Δ haze is 0.5% or more, the change in haze value before and
after heat treatment is visually apparent.

[0113] (4) Measurement of Resin Layer Thickness d

[0114] Ten samples were randomly taken out of a laminated film by
dyeing-freezing superthin section method using RuO4 staining and
observed under a TEM (transmission electron microscope: H-7100FA
manufactured by Hitachi Ltd.) at a magnification of 10000 to
1000000×, at which magnification the cross section structure can be
visually observed, and photographs were taken. Each resin layer thickness
was measured from the ten cross-section photographs, and the mean value
was taken as the resin layer thickness d.

[0116] Samples were randomly taken out of a laminated film by
dyeing-freezing superthin section method using RuO4 staining and
observed under a TEM (transmission electron microscope: H-7100FA
manufactured by Hitachi Ltd.) at a magnification of 10000 to
1000000×, at which magnification the form of inorganic particles
can be visually observed from a cross section, and 100 or more
photographs of inorganic particles were taken. From 100
inorganic-particle cross-section photographs randomly selected from them,
each particle size was measured in nanometers. In the case where the
particle was a perfect circle, an arbitrary diameter was measured, and in
the case where the particle was oval, the shortest diameter was measured.
The particle sizes measured were converted in such a manner that the last
digit was converted to 0 in the case where the last digit was 0, 1, or 2;
the last digit was converted to 5 in the case where the last digit was 3,
4, 5, 6, or 7; and the last digit was converted to 0 and the second last
digit was increased by 1 in the case where the last digit was 8 or 9. For
example, in the case where the particle size measured was 98 to 102 nm,
it was converted to 100 nm, and in the case where the particle size
measured was 103 to 107 nm, it was converted to 105 nm. The particle
sizes thus converted was plotted in a graph of frequency distribution in
which the abscissa represents particle size (nm) and the ordinate
represents frequency. In the case where a plurality of particle sizes
having the same frequency was present, peaks of the distribution were
numbered in order of decreasing particle size as mentioned above.

[0117] (6) Pressure Treatment Evaluation

[0118] In a pressure treatment test, samples were pressurized at a
pressure of 10 kgf/cm2 for one hour using a mechanical bench press
(plastic film production equipment, G-12 type: manufactured by
Technosupply Co. Ltd.) in normalcy (23° C., relative humidity:
65%), then subjected to a heat treatment by the same method as in (3)
Heat-treatment evaluation, and evaluated as Δ haze value. As a
sample, those which were obtained by laminating five laminated films
sized to 15 cm×20 cm such that the surface of the laminated film on
which surface a resin layer was not laminated and the resin layer surface
of another laminated film were in contact was used. In the case of a
laminated film on both surfaces of which resin layers were laminated,
resin layer surfaces were laminated on each other. The evaluation
criteria are the same as in (3).

<Δ Haze Value>

[0119] A: Less than 0.3% B: Not less than 0.3% and less than 0.5% C: 0.5%
or more

[0120] Our films will be described more specifically by way of Examples.
However, this disclosure is not limited to the following Examples. In
both of the following Examples and Comparative Examples, the value of the
number-average particle size of inorganic particles added into a resin
composition was the peak position of the particle-size distribution of
inorganic particles.

For the polyester resin component, terephthalic acid, isophthalic acid,
ethylene glycol, and diethylene glycol were charged together with a
polymerization catalyst into a reactor purged with nitrogen, and a
polymerization reaction was carried out under normal pressure at 190 to
220° C. for 12 hours while removing water to obtain a polyester
glycol. The polyester glycol obtained, 5-sodium sulfoisophthalic acid,
and xylene as a solvent were charged into a reactor and allowed to
polymerize for 3 hours while distilling off the xylene to obtain the
polyester resin component. The polyester resin component was dissolved in
aqueous ammonia and butyl cellulose-containing water.

[0124] Next, for an acrylic resin component having a Tg=77° C., an
acrylic resin component having a mass ratio of isopropyl methacrylate
(single polymer Tg: 81° C.)/glycidyl methacrylate (single polymer
Tg: 41° C.)=90/10 was added together with a polymerization
initiator into a water dispersion containing the above-described
polyester resin component such that the mass ratio of the acrylic resin
component/the polyester resin component=50/50, and a polymerization
reaction was carried out in a reactor purged with nitrogen at 70 to
80° C. for 3 hours to obtain an acrylic-modified polyester.

[0125] Sugar Alcohol (B1):

[0126] D-glucitol (boiling point: 296° C., available from NACALAI
TESQUE, INC.) was dissolved in pure water for preparation.

[0127] Aqueous Solvent (F): Pure Water

[0128] The acrylic-modified polyester (A) and the sugar alcohol (B1) were
mixed and adjusted to have a mass ratio of (A/B1)=97/3, i.e.,
(A/(B1+B2))=97/3. To impart smoothness to the laminated film surface
after resin layer formation, silica particles having a number-average
particle size of 170 nm (SNOWTEX (registered trademark) MP-2040 available
from NISSAN CHEMICAL INDUSTRIES, LTD.) were added as the inorganic
particles (D) in an amount of 2 parts by mass based on 100 parts by mass
of the total of the acrylic-modified polyester (A) and the sugar alcohol
(B1). In addition, to improve the application properties of the resin
composition onto a thermoplastic resin film, the fluorochemical
surfactant (E) (PLAS COAT (registered trademark) RY-2 available from GOO
CHEMICAL CO., LTD.) was added such that the content based on the total
resin composition was 0.02% by mass.

[0129] Next, PET pellets (limiting viscosity: 0.63 dl/g) substantially
free of particles were sufficiently vacuum-dried and then fed to an
extruder for melting at 285° C. Then, the melted polymer was
extruded through a T-die into a sheet and wound around a mirror-finished
casting drum at a surface temperature of 25° C. using an
electro-pinning casting method to solidify by cooling. This undrawn film
was drawn 3.4-fold in the longitudinal direction by heating to 90°
C. to obtain a uniaxially drawn film (B film).

[0130] Next, a resin composition was applied to a corona discharge
treatment surface of the uniaxially drawn film using a bar coater at a
coating thickness of about 12 μm. The uniaxially drawn film coated
with the resin composition was guided to a preheating zone with both ends
in the width direction held by clips. After adjusting the ambient
temperature to 75° C., the ambient temperature was subsequently
adjusted to 110° C. using a radiation heater, and then the ambient
temperature was adjusted to 90° C. to dry the composition for
coating to thereby form a composition layer. Subsequently, the uniaxially
drawn film was continuously drawn 3.5-fold in the width direction in a
heating zone (drawing zone) at 120° C., and then subjected to a
heat treatment in a heat treatment zone (heat fixation zone) at
230° C. for 20 seconds to obtain a laminated film with its crystal
orientation being completed. In the laminated film obtained, the
thickness of the PET film was 100 μm, and the thickness of the resin
layer was about 0.15 μm. The properties of the laminated film obtained
are shown in the Tables. The transparency such as haze and total light
transmittance was excellent, and the Δ haze after 1-hour heat
treatment at 140° C. and pressure treatment was less than 0.3%;
thus the results of the heat-treatment evaluation were good.

Examples 2 to 6

[0131] A laminated film was obtained in the same manner as in Example 1
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. By
increasing the mass ratio of the sugar alcohol (B1) in the order from
Examples 2 to 6, homogeneous film-formation of the acrylic-modified
polyester (A) was improved; initial haze was reduced compared to Example
1; and the Δ haze after 1-hour heat treatment at 140° C. and
pressure treatment was less than 0.3%; thus the results of the
heat-treatment evaluation were good.

Example 7

[0132] A laminated film was obtained in the same manner as in Example 1
except that the acrylic-modified polyester (A) and the sugar alcohol (B1)
used in Example 1 and besides the oxazoline-based compound (C) described
below were adjusted to have a mass ratio of (A/B1/C)=95/5/10, i.e.,
(A/(B1+B2)/C)=95/5/10.

[0134] The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 2 using the same mass ratio of
(A/(B1+B2)), the inclusion of the oxazoline-based compound (C) further
reduced the Δ haze after 1-hour heat treatment at 140° C.
while maintaining the transparency such as haze and total light
transmittance; thus the results of the heat-treatment evaluation were
good. On the other hand, the pressure treatment evaluation showed such
somewhat poor results compared to Example 2 that degradation of the resin
layer due to friction between resin layers and local pressure slightly
occurred because the number-average particle size of an inorganic
particle group was less than particle size 1.05 d.

Examples 8, 9

[0135] A laminated film was obtained in the same manner as in Example 7
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) to the compound (C) was changed to the values
described in the Tables. The properties of the laminated film obtained
are shown in the Tables. Although the mass ratio of the oxazoline-based
compound (C) was increased in the order from Examples 8 to 9, similarly
to the results of Example 7, the Δ haze after 1-hour heat treatment
at 140° C. was more reduced than in Example 2 while the
transparency such as haze and total light transmittance were maintained;
thus the results of the heat-treatment evaluation were good. On the other
hand, the pressure treatment evaluation showed such somewhat poor results
similar to Example 7 that degradation of the resin layer due to friction
between resin layers and local pressure slightly occurred because the
number-average particle size of an inorganic particle group was less than
particle size 1.05 d.

Example 10

[0136] A laminated film was obtained in the same manner as in Example 1
except that the acrylic resin component in the acrylic-modified polyester
(A) was adjusted to have a mass ratio of methyl methacrylate (single
polymer Tg: 105° C.)/glycidyl methacrylate (single polymer Tg:
41° C.)=90/10. The Tg of the acrylic resin component in the
acrylic-modified polyester (A) was 97° C. The properties of the
laminated film obtained are shown in the Tables. In comparison with
Example 1, since the Tg of the acrylic resin component of the
acrylic-modified polyester was high, the Δ haze after 1-hour heat
treatment at 140° C. and pressure treatment was more reduced
although the initial haze value was slightly increased; thus the results
of the heat-treatment evaluation were good.

Examples 11 to 15

[0137] A laminated film was obtained in the same manner as in Example 10
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. In
comparison with Examples 2 to 6 using the same mass ratio of (A/(B1+B2))
as in Examples 11 to 15, respectively, since the Tg of the acrylic resin
component of the acrylic-modified polyester was high, the effect of
oligomer inhibition was improved, and each Δ haze after 1-hour heat
treatment at 140° C. and pressure treatment was more reduced while
maintaining the transparency such as haze and total light transmittance;
thus the results of the heat-treatment evaluation were good.

Example 16

[0138] A laminated film was obtained in the same manner as in Example 10
except that the acrylic-modified polyester (A) and the sugar alcohol (B1)
used in Example 10 and besides the compound (C) used in Example 7 was
adjusted to have a mass ratio of (A/B1/C)=90/10/10, i.e.,
(A/(B1+B2)/C)=90/10/10. The properties of the laminated film obtained are
shown in the Tables. In comparison with Example 13 using the same mass
ratio of (A/(B1+B2)), although the transparency such as haze and total
light transmittance and the Δ haze after 1-hour heat treatment at
140° C. were somewhat poor because of the inclusion of the
oxazoline-based compound (C), the haze was not more than 2%, and the
Δ haze after 1-hour heat treatment at 140° C. and pressure
treatment was less than 0.3%; thus the results of the heat-treatment
evaluation were good.

Examples 17, 18

[0139] A laminated film was obtained in the same manner as in Example 16
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) to the compound (C) was changed to the values
described in the Tables. The properties of the laminated film obtained
are shown in the Tables. Although the mass ratio of the oxazoline-based
compound (C) was increased in the order from Examples 17 to 18, in
comparison with Example 13, although the transparency such as haze and
total light transmittance and the Δ haze after 1-hour heat
treatment at 140° C. were somewhat poor similarly to the results
of Example 16, the haze was not more than 2%, and the Δ haze after
1-hour heat treatment at 140° C. and pressure treatment was less
than 0.3%; thus the results of the heat-treatment evaluation were good.
However, in comparison with Examples 8 and 9, the Δ haze was
reduced because the Tg of the acrylic resin component in the
acrylic-modified polyester (A) was high.

Example 19

[0140] A laminated film was obtained in the same manner as in Example 10
except that the acrylic-modified polyester (A) and the sugar alcohol (B1)
used in Example 10 and besides the carbodiimide-based compound (C)
described below were adjusted to have a mass ratio of (A/B1/C)=90/10/30,
i.e., (A/(B1+B2)/C)=90/10/30.

[0142] The properties of the laminated film obtained are shown in the
Tables. The results were the same as in Example 17 using the
oxazoline-based compound (C), and in comparison with Example 13, although
the transparency such as haze and total light transmittance and the A
haze after 1-hour heat treatment at 140° C. were somewhat poor,
the haze was not more than 2%, and the Δ haze after 1-hour heat
treatment at 140° C. and pressure treatment was less than 0.3%;
thus the results of the heat-treatment evaluation were good. However, in
comparison with Example 8, the Δ haze was reduced because the Tg of
the acrylic resin component in the acrylic-modified polyester (A) was
high.

Example 20

[0143] A laminated film was obtained in the same manner as in Example 10
except that the acrylic-modified polyester (A) was prepared to have a
mass ratio of the acrylic resin component/the polyester resin
component=30/70 and that the mass ratio of the acrylic-modified polyester
(A) to the sugar alcohol (B1) was changed to the values described in the
Tables. The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 13 using the same mass ratio of
(A/(B1+B2)), although the oligomer-inhibiting effect was somewhat poor
because the acrylic resin component in the acrylic-modified polyester (A)
was decreased, the Δ haze after 1-hour heat treatment at
140° C. was less than 0.3%; thus the results of the heat-treatment
evaluation were good.

Example 21

[0144] A laminated film was obtained in the same manner as in Example 10
except that the acrylic-modified polyester (A) was prepared to have a
mass ratio of the acrylic resin component/the polyester resin
component=90/10 and that the mass ratio of the acrylic-modified polyester
(A) to the sugar alcohol (B1) was changed to the values described in the
Tables. The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 13 using the same mass ratio of
(A/(B1+B2)), since the acrylic resin component in the acrylic-modified
polyester (A) was increased, the transparency such as haze and total
light transmittance were slightly improved, and the oligomer-inhibiting
effect was maintained; thus the results of the heat-treatment evaluation
were good.

Example 22

[0145] A laminated film was obtained in the same manner as in Example 10
except that the acrylic resin component in the acrylic-modified polyester
(A) was adjusted to have a mass ratio of methyl methacrylate (single
polymer Tg: 105° C.)/glycidyl methacrylate (single polymer Tg:
41° C.)=97/3 and that the mass ratio of the acrylic-modified
polyester (A) to the sugar alcohol (B1) was changed to the values
described in the Tables. The Tg of the acrylic resin component in the
acrylic-modified polyester (A) was 103° C. The properties of the
laminated film obtained are shown in the Tables. In comparison with
Example 13 using the same mass ratio of (A/(B1+B2)), although the
homogeneous film-formation of the acrylic-modified polyester (A) was
slightly deteriorated and the initial haze was slightly increased because
the Tg of the acrylic resin component in the acrylic-modified polyester
(A) was high, the Δ haze after 1-hour heat treatment at 140°
C. and pressure treatment were more reduced; thus the results of the
heat-treatment evaluation were good.

Example 23

[0146] A laminated film was obtained in the same manner as in Example 10
except that the acrylic resin component in the acrylic-modified polyester
(A) was adjusted to have a mass ratio of methyl methacrylate (single
polymer Tg: 105° C.)/glycidyl methacrylate (single polymer Tg:
41° C.)=50/50 and that the mass ratio of the acrylic-modified
polyester (A) to the sugar alcohol (B1) was changed to the values
described in the Tables. The Tg of the acrylic resin component in the
acrylic-modified polyester (A) was 70° C. The properties of the
laminated film obtained are shown in the Tables. In comparison with
Example 4 using the same mass ratio of (A/(B1+B2)), although the Δ
haze after 1-hour heat treatment at 140° C. and pressure treatment
was slightly increased because the Tg of the acrylic resin component in
the acrylic-modified polyester (A) was low, the Δ haze was less
than 0.3%; thus the results of the heat-treatment evaluation were good.

Example 24

[0147] A laminated film was obtained in the same manner as in Example 10
except that the acrylic-modified polyester (A) was prepared to have a
mass ratio of the acrylic resin component/the polyester resin
component=20/80 and that the mass ratio of the acrylic-modified polyester
(A) to the sugar alcohol (B1) was changed to the values described in the
Tables. The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 20 using the same mass ratio of
(A/(B1+B2)), although the oligomer-inhibiting effect was somewhat poor
because the acrylic resin component in the acrylic-modified polyester (A)
was decreased, the Δ haze after 1-hour heat treatment at
140° C. was less than 0.3%; thus the results of the heat-treatment
evaluation were good.

Example 25

[0148] A laminated film was obtained in the same manner as in Example 10
except that the acrylic resin component in the acrylic-modified polyester
(A) was adjusted to have a mass ratio of methyl methacrylate (single
polymer Tg: 105° C.)/glycidyl methacrylate (single polymer Tg:
41° C.)=45/55 and that the mass ratio of the acrylic-modified
polyester (A) to the sugar alcohol (B1) was changed to the values
described in the Tables. The Tg of the acrylic resin component in the
acrylic-modified polyester (A) was 67° C. The properties of the
laminated film obtained are shown in the Tables. In comparison with
Example 23 using the same mass ratio of (A/(B1+B2)), although the Δ
haze after 1-hour heat treatment at 140° C. was slightly increased
because the Tg of the acrylic resin component in the acrylic-modified
polyester (A) was low, the Δ haze was less than 0.3%; thus the
results of the heat-treatment evaluation were good.

Example 26

[0149] A laminated film was obtained in the same manner as in Example 13
except that the number average particle size of silica particles was
changed to 80 nm (Cataloid (registered trademark) SI-80P available from
Catalysts & Chemicals Ind. Co., Ltd.) and that the resin layer thickness
d was 75 nm. The properties of the laminated film obtained are shown in
the Tables. In comparison with Example 13, the value of the Δ haze
after 1-hour heat treatment at 140° C. was somewhat poor because
the small number-average particle size of the silica particles increased
the particle number in the same amount and the gap between the silica
particles and a binder resin of the resin layer was increased, but this
was practically acceptable. Further, in comparison with Example 13, the
value of the Δ haze after pressure treatment evaluation was
somewhat poor because the ratio of (number average particle size of
inorganic particle size (peak position of particle-size
distribution)/resin layer thickness d) was as small as 1.07 and the space
between laminated films was narrow, but this was practically acceptable.

Example 27

[0150] A laminated film was obtained in the same manner as in Example 13
except that the number average particle size of silica particles was
changed to 150 nm (SPHERICA (registered trademark) slurry 140 available
from JGC C&C.) and that the resin layer thickness d was 75 nm. The
properties of the laminated film obtained are shown in the Tables. In
comparison with Example 13, although the thickness of the resin layer was
reduced, the resin layers had the same composition ratio, and the silica
particles had substantially the same number-average particle size, so
that both the Δ haze after 1-hour heat treatment at 140° C.
and pressure treatment and the Δ haze after heat treatment were
equivalent; thus the results were good.

Example 28

[0151] A laminated film was obtained in the same manner as in Example 13
except that the number average particle size of silica particles was
changed to 300 nm (SEAHOSTAR (registered trademark) KE-W30 available from
NIPPON SHOKUBAI CO., LTD.) and that the resin layer thickness d was 75
nm. The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 13, although the thickness of the
resin layer was reduced, the resin layers had the same composition ratio,
and the number-average particle size of the silica particles was
increased only to the extent that heat-treatment evaluation was not
affected, so that the Δ haze after 1-hour heat treatment at
140° C. was equivalent; thus the results were good. In comparison
with Example 13, since the ratio of (number average particle size of
inorganic particle size (peak position of particle-size
distribution)/resin layer thickness d) was as large as 4.00 and there was
a sufficient gap between laminated films, the Δ haze after pressure
treatment evaluation was equivalent; thus the results were good.

Example 29

[0152] A laminated film was obtained in the same manner as in Example 13
except that the number average particle size of silica particles was
changed to 335 nm (SNOWTEX (registered trademark) MP-3040 available from
NISSAN CHEMICAL INDUSTRIES, LTD.) and that the resin layer thickness d
was 75 nm. The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 13, the value of the Δ haze
after 1-hour heat treatment at 140° C. was somewhat poor because
the increased number-average particle size of the silica particles
increased the contact area between the silica particles and the binder
resin of the resin layer in the same amount and the gap between the
silica particles and the binder resin of the resin layer was increased,
but this was practically acceptable. Also, in the pressure treatment
evaluation, although the value of the Δ haze after pressure
treatment evaluation was also somewhat poor for the same reason because
heating was performed after pressurization, the results were good.

Examples 30 to 33

[0153] A laminated film was obtained in the same manner as in Example 27
except that the amount of silica particles (D) was changed to 0.2, 1.0,
3.0, and 4.0 parts by mass based on 100 parts by mass of the total of the
acrylic-modified polyester resin (A) and the sugar alcohol (B1). In
comparison with Example 27, in Example 30 in which the amount of (D) was
0.2 parts by mass, since the smoothness between laminated films was poor
because of the small amount of silica particles, the resin layer was
slightly deteriorated by the friction between laminated films upon
handling, for example, in heat treatment, resulting in somewhat poor
value of the Δ haze after heat treatment, but the results were
practically acceptable. Further, since the gap between laminated films
was somewhat hard to maintain compared to Example 27 because of the small
amount of silica particles, the value of the Δ haze after pressure
treatment was somewhat poor, but the results were practically acceptable.

[0154] In Examples 31 and 32, since the amount of silica particles was
substantially the same as in Example 27, the Δ haze after heat
treatment and after pressure treatment was almost the same; thus the
results were good.

[0155] In Example 33, in comparison with Example 27, since the gap between
silica particles and a binder resin of the resin layer was increased
because of an increased amount of silica particles, the value of the
Δ haze after 1-hour heat treatment at 140° C. was somewhat
poor, but the results were practically acceptable. Also in the pressure
treatment evaluation, although the value of the Δ haze after
pressure treatment evaluation was also somewhat poor for the same reason
because heating was performed after pressurization, the results were
practically acceptable.

Examples 34 to 36

[0156] A laminated film was obtained in the same manner as in Example 27
except that the silica particles were changed to two types of particles
having a number average particle size of 150 nm and 300 nm and added in
the amount described in the Tables. The properties of the laminated film
obtained are shown in the Tables. Further addition of 300-nm particles in
an appropriate amount to Example 27 provided the laminated film with
sufficient smoothness, so that the A haze after heat treatment was
equivalent or more; thus the results were good. Further, the ratio of
number-average particle size of inorganic particles (peak position of
particle-size distribution)/resin layer thickness d) was 2.00/4.00, while
it was 2.00 in Example 27, and there was sufficient space between the
laminated films, so that the Δ haze after pressure treatment
evaluation was equivalent or more; thus the results were good.

Examples 37 to 40

[0157] A laminated film was obtained in the same manner as in Example 27
except that the amount of the fluorochemical surfactant (E) was changed
to 0.01, 0.05, 0.1, and 0.3% by mass based on the total resin
composition. The properties of the laminated film obtained are shown in
the Tables. As in Example 27, since the amount of the fluorochemical
surfactant was preferable, the Δ haze after 1-hour heat treatment
at 140° C. and the Δ haze after pressure treatment
evaluation were both equivalent; thus the results were good.

Examples 41, 42

[0158] A laminated film was obtained in the same manner as in Example 35
except that the amount of the fluorochemical surfactant (E) was changed
to 0.05 and 0.1% by mass based on the total resin composition. The
properties of the laminated film obtained are shown in the Tables. As in
Example 35, since the amount of the fluorochemical surfactant was
preferable, the Δ haze after 1-hour heat treatment at 140°
C. and the Δ haze after pressure treatment evaluation were both
equivalent; thus the results were good.

Example 43

[0159] A laminated film was obtained in the same manner as in Example 40
except that the oxazoline-based compound (C) used in Example 7 was added
in an amount of 10 parts by mass based on 100 parts by mass of the total
of the acrylic-modified polyester (A) and the sugar alcohol (B1). The
properties of the laminated film obtained are shown in the Tables. In
comparison with Example 40, since the abundance ratio of the
acrylic-modified polyester (A) was decreased relative to the same resin
layer thickness, both of the values of the Δ haze after 1-hour heat
treatment at 140° C. and the Δ haze after pressure treatment
evaluation were poor, but the results were practically acceptable.

Example 44

[0160] A laminated film was obtained in the same manner as in Example 42
except that the oxazoline-based compound (C) used in Example 7 was added
in an amount of 10 parts by mass based on 100 parts by mass of the total
of the acrylic-modified polyester (A) and the sugar alcohol (B1). The
properties of the laminated film obtained are shown in the Tables. In
comparison with Example 42, since the abundance ratio of the
acrylic-modified polyester (A) was decreased relative to the same resin
layer thickness, both of the values of the Δ haze after 1-hour heat
treatment at 140° C. and the Δ haze after pressure treatment
evaluation were poor, but the results were practically acceptable.

Example 45

[0161] A laminated film was obtained in the same manner as in Example 40
except that the oxazoline-based compound (C) used in Example 7 was added
in an amount of 30 parts by mass based on 100 parts by mass of the total
of the acrylic-modified polyester (A) and the sugar alcohol (B1). The
properties of the laminated film obtained are shown in the Tables. In
comparison with Example 40, since the abundance ratio of the
acrylic-modified polyester (A) was decreased relative to the same resin
layer thickness, both of the values of the Δ haze after 1-hour heat
treatment at 140° C. and the Δ haze after pressure treatment
evaluation were poor, but the results were practically acceptable.

Example 46

[0162] A laminated film was obtained in the same manner as in Example 42
except that the oxazoline-based compound (C) used in Example 7 was added
in an amount of 30 parts by mass based on 100 parts by mass of the total
of the acrylic-modified polyester (A) and the sugar alcohol (B1). The
properties of the laminated film obtained are shown in the Tables. In
comparison with Example 42, since the abundance ratio of (A) was
decreased relative to the same resin layer thickness, both of the values
of the Δ haze after 1-hour heat treatment at 140° C. and the
Δ haze after pressure treatment evaluation were poor, but the
results were practically acceptable.

Example 47

[0163] A laminated film was obtained in the same manner as in Example 1
except that the acrylic resin component in the acrylic-modified polyester
(A) was adjusted to have a mass ratio of methyl methacrylate (single
polymer Tg: 105° C.)/glycidyl methacrylate (single polymer Tg:
41° C.)=85/15. The Tg of the acrylic resin component in the
acrylic-modified polyester (A) was 93° C. The properties of the
laminated film obtained are shown in the Tables. In comparison with
Example 1, since the Tg of the acrylic resin component of the
acrylic-modified polyester was high, the Δ haze after 1-hour heat
treatment at 140° C. and pressure treatment was more reduced
although the initial haze value was slightly increased; thus the results
of the heat-treatment evaluation were good.

Examples 48 to 52

[0164] A laminated film was obtained in the same manner as in Example 1
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. By
increasing the mass ratio of (B1+B2) in the order from Examples 48 to 52,
homogeneous film-formation of the acrylic-modified polyester (A) was
improved; initial haze was reduced compared to Example 47; and the
Δ haze after 1-hour heat treatment at 140° C. and pressure
treatment was less than 0.3%; thus the results of the heat-treatment
evaluation were good.

Example 53

[0165] A laminated film was obtained in the same manner as in Example 47
except that the acrylic-modified polyester (A) and the sugar alcohol (B1)
used in Example 47 and besides the compound (C) used in Example 7 was
adjusted to have a mass ratio of (A/B1/C)=90/10/10, i.e.,
(A/(B1+B2)/C)=90/10/10. The properties of the laminated film obtained are
shown in the Tables. In comparison with Example 50 using the same mass
ratio of (A/(B1+B2)), although the transparency such as haze and total
light transmittance and the Δ haze after 1-hour heat treatment at
140° C. were somewhat poor because of the inclusion of the
compound (C) comprising an oxazoline-based compound, the haze was not
more than 2%, and the Δ haze after 1-hour heat treatment at
140° C. and pressure treatment was less than 0.3%; thus the
results of the heat-treatment evaluation were good.

Examples 54, 55

[0166] A laminated film was obtained in the same manner as in Example 53
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) to the compound (C) was changed to the values
described in the Tables. The properties of the laminated film obtained
are shown in the Tables. Although the mass ratio of the compound (C)
comprising an oxazoline-based compound was increased in the order from
Examples 54 to 55, in comparison with Example 50, although the
transparency such as haze and total light transmittance and the Δ
haze after 1-hour heat treatment at 140° C. were somewhat poor
similarly to the results of Example 53, the haze was not more than 2%,
and the Δ haze after 1-hour heat treatment at 140° C. and
pressure treatment was less than 0.3%; thus the results of the
heat-treatment evaluation were good. However, in comparison with Examples
7 and 8, the Δ haze was reduced because the Tg of the acrylic resin
component in the acrylic-modified polyester (A) was high.

Example 56

[0167] A laminated film was obtained in the same manner as in Example 10
except that the acrylic-modified polyester (A) and the sugar alcohol (B1)
used in Example 10 and besides the epoxy-based compound (C) described
below were adjusted to have a mass ratio of (A/B1/C)=90/10/30, i.e.,
(A/(B1+B2)/C)=90/10/30.

[0169] The properties of the laminated film obtained are shown in the
Tables. The results were the same as in Example 17 using the
oxazoline-based compound (C), and in comparison with Example 13, although
the transparency such as haze and total light transmittance and the
Δ haze after 1-hour heat treatment at 140° C. were somewhat
poor, the haze was not more than 2%, and the Δ haze after 1-hour
heat treatment at 140° C. and pressure treatment was less than
0.3%; thus the results of the heat-treatment evaluation were good.

Example 57

[0170] A laminated film was obtained in the same manner as in Example 10
except that the acrylic-modified polyester (A) and the sugar alcohol (B1)
used in Example 10 and besides the melamine-based compound (C) described
below were adjusted to have a mass ratio of (A/B1/C)=90/10/30, i.e.,
(A/(B1+B2)/C)=90/10/30.

[0172] The properties of the laminated film obtained are shown in the
Tables. The results were the same as in Example 17 using the
oxazoline-based compound (C), and in comparison with Example 13, although
the transparency such as haze and total light transmittance and the
Δ haze after 1-hour heat treatment at 140° C. were somewhat
poor, the haze was not more than 2%, and the Δ haze after 1-hour
heat treatment at 140° C. and pressure treatment was less than
0.3%; thus the results of the heat-treatment evaluation were good.

Example 58

[0173] The acrylic-modified polyester (A) used in Example 10 and the sugar
alcohol derivative (B2) below were adjusted to have a mass ratio of
(A/B2)=90/10, i.e., (A/(B1+B2))=90/10, and a laminated film was obtained
in the same manner as in Example 13.

[0175] The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 13 using the sugar alcohol (B1),
although the transparency such as haze and total light transmittance and
the Δ haze after 1-hour heat treatment at 140° C. were
somewhat poor, the haze was not more than 2%, and the Δ haze after
1-hour heat treatment at 140° C. and pressure treatment was less
than 0.3%; thus the results of the heat-treatment evaluation were good.

Example 59

[0176] The acrylic-modified polyester (A) used in Example 10 and the sugar
alcohol derivative (B2) below were adjusted to have a mass ratio of
(A/B2)=90/10, i.e., (A/(B1+B2))=90/10, and a laminated film was obtained
in the same manner as in Example 13.

[0178] The properties of the laminated film obtained are shown in the
Tables. In comparison with Example 13 using the sugar alcohol (B1),
although the transparency such as haze and total light transmittance and
the Δ haze after 1-hour heat treatment at 140° C. were
somewhat poor, the haze was not more than 2%, and the Δ haze after
1-hour heat treatment at 140° C. and pressure treatment was less
than 0.3%; thus the results of the heat-treatment evaluation were good.

Comparative Example 1

[0179] A laminated film was obtained in the same manner as in Example 1
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. The
mass ratio of the acrylic-modified polyester (A) to the sugar alcohol
(B1) was (A/B1) 72/28, i.e., (A/(B1+B2))=72/28; the ratio of (A) was less
than 0.75 (that is, the ratio of the total of (B1+B2) was more than
0.25). Therefore, in comparison with, for example, Example 6 in which the
acrylic component in the acrylic-modified polyester (A) had the same Tg
and the mass ratio of (A/(B1+B2)) was most approximate, although the
transparency such as initial haze and total light transmittance was
equivalent, the effect of oligomer inhibition of the acrylic-modified
polyester (A) was insufficient, resulting in that the Δ haze after
1-hour heat treatment at 140° C. was more than 0.3%; thus the
results of the heat-treatment evaluation was poor.

Comparative Example 2

[0180] A laminated film was obtained in the same manner as in Example 1
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. The
mass ratio of the acrylic-modified polyester (A) to the sugar alcohol
(B1) was (A/B1)=-99/1, i.e., (A/(B1+B2))=99/1; the ratio of the total of
(B1+B2) was less than 0.03 (the ratio of (A) was more than 0.97).
Therefore, in comparison with, for example, Example 1 in which the
acrylic component in the acrylic-modified polyester (A) had the same Tg
and the mass ratio of (A/(B1+B2)) was most approximate, the imparting of
homogeneous film-formation from the sugar alcohol (B1) to the
acrylic-modified polyester (A) was insufficient, which caused cracks in
the resin layer, resulting in that the initial haze was not less than
2.0%; thus the transparency was poor. In addition, oligomers precipitated
from the cracks in the resin layer and, therefore the A haze after 1-hour
heat treatment at 140° C. was more than 0.3%; thus the results of
the heat-treatment evaluation was poor.

Comparative Example 3

[0181] A laminated film was obtained in the same manner as in Example 1
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. The
mass ratio of the acrylic-modified polyester (A) to the sugar alcohol
(B1) was (A/B1)=72/28, i.e., (A/(B1+B2))=72/28; the ratio of (A) was less
than 0.75 (that is, the ratio of the total of (B1+B2) was more than
0.25). Therefore, in comparison with, for example, Example 15 in which
the acrylic component in the acrylic-modified polyester (A) had the same
Tg and the mass ratio of (A/(B1+B2)) was most approximate, although the
transparency such as initial haze and total light transmittance was
equivalent, the effect of oligomer inhibition of the acrylic-modified
polyester (A) was insufficient, resulting in that the Δ haze after
1-hour heat treatment at 140° C. was more than 0.3%; thus the
results of the heat-treatment evaluation was poor.

Comparative Example 4

[0182] A laminated film was obtained in the same manner as in Example 7
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. The
mass ratio of the acrylic-modified polyester (A) to the sugar alcohol
(B1) was (A/B1)=99/1, i.e., (A/(B1+B2))=99/1, the ratio of the total of
(B1+B2) was less than 0.03 (the ratio of (A) was more than 0.97).
Therefore, in comparison with Example 10 in which the acrylic component
in the acrylic-modified polyester (A) had the same Tg and the mass ratio
of (A/(B1+B2)) was most approximate, the imparting of homogeneous
film-formation from the sugar alcohol (B1) to the acrylic-modified
polyester (A) was insufficient, which caused cracks in the resin layer,
resulting in that the initial haze was not less than 2.0%; thus the
transparency was poor. In addition, oligomers precipitated from the
cracks in the resin layer and, therefore the A haze after 1-hour heat
treatment at 140° C. was more than 0.3%; thus the results of the
heat-treatment evaluation was poor.

Comparative Example 5

[0183] A laminated film was obtained in the same manner as in Example 1
except using one prepared by dissolving ethylene glycol (boiling point:
197° C., available from Kanto Chemical Industry Co., Ltd.) in pure
water in place of D-glucitol as a sugar alcohol (B1). Ethylene glycol is
not a sugar alcohol (B1) or a sugar alcohol derivative (B2). The
properties of the laminated film obtained are shown in the Tables. In a
laminated film-forming process, a heat treatment was applied for 20
seconds at a heat treatment zone (heat fixation zone) at 230° C.,
which is higher than the boiling point of ethylene glycol, and therefore
the ethylene glycol in the resin layer precipitated from inside the resin
layer and evaporated, causing cracks in the resin layer. The crack
generation resulted in that the initial haze was not less than 2.0%, and
thus the transparency was poor. In addition, since oligomers precipitated
from the cracks, the Δ haze after 1-hour heat treatment at
140° C. was more than 0.3%, and thus the results of the
heat-treatment evaluation was poor.

Comparative Example 6

[0184] A laminated film was obtained in the same manner as in Example 1
except that the acrylic resin component in the acrylic-modified polyester
(A) was adjusted to have a mass ratio of ethyl methacrylate (single
polymer Tg: 65° C.)/glycidyl methacrylate (single polymer Tg:
41° C.)=90/10. The properties of the laminated film obtained are
shown in the Tables. The Tg of the acrylic resin component in the
acrylic-modified polyester (A) was 62° C. The Tg of the acrylic
resin component in the acrylic-modified polyester (A) was not more than
67° C., and, in comparison with Example 4 using the same mass
ratio of (A/(B1+B2)), the transparency such as initial haze and total
light transmittance was equivalent. However, the effect of oligomer
inhibition was insufficient, resulting in that the Δ haze after
1-hour heat treatment at 140° C. was more than 0.3%, and thus the
results of the heat-treatment evaluation was poor.

Comparative Example 7

[0185] A laminated film was obtained in the same manner as in Example 10
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. The
mass ratio of the acrylic-modified polyester (A) to the sugar alcohol
(B1) was (A/B1)=100/0, i.e., (A/(B1+B2))=100/0, meaning that only (A) was
contained, and the ratio of the total of (B1+B2) was less than 0.03 (the
ratio of (A) was more than 0.97). Therefore, in comparison with Example
10 in which the acrylic component in the acrylic-modified polyester (A)
had the same Tg and the mass ratio of (A/(B1+B2)) was most approximate,
the imparting of homogeneous film-formation from the sugar alcohol (B1)
to the acrylic-modified polyester (A) was severely deficient, which
caused cracks in the resin layer, resulting in that the initial haze was
not less than 2.0%; thus the transparency was poor. In addition,
oligomers precipitated from the cracks in the resin layer and, therefore
the Δ haze after 1-hour heat treatment at 140° C. was more
than 0.3%; thus the results of the heat-treatment evaluation was poor.

Comparative Example 8

[0186] A laminated film was obtained in the same manner as in Example 10
except that the mass ratio of the acrylic-modified polyester (A) to the
sugar alcohol (B1) was changed to the values described in the Tables. The
properties of the laminated film obtained are shown in the Tables. The
mass ratio of the acrylic-modified polyester (A) to the sugar alcohol
(B1) was (A/B1)=100/0, i.e., (A/(B1+B2))=100/0, meaning that only (A) was
contained; the ratio of the total of (B1+B2) was less than 0.03 (the
ratio of (A) was more than 0.97). Therefore, in comparison with Example 1
in which the acrylic component in the acrylic-modified polyester (A) had
the same Tg and the mass ratio of (A/(B1+B2)) was most approximate, the
imparting of homogeneous film-formation from the sugar alcohol (B1) to
the acrylic-modified polyester (A) was severely deficient, which caused
cracks in the resin layer, resulting in that the initial haze was not
less than 2.0%; thus the transparency was poor. In addition, oligomers
precipitated from the cracks in the resin layer and, therefore the
Δ haze after 1-hour heat treatment at 140° C. was more than
0.3%; thus the results of the heat-treatment evaluation was poor.

[0187] The composition and evaluation results of each Example and
Comparative Example are summarized in Tables 1 to 15. For Comparative
Example 5, (B1+B2) represents the mass of ethylene glycol.

[0188] We provide a laminated film that is transparent and has an
excellent ability to inhibit oligomers due to heat treatment, and the
film can be used in optical adhesion films for display application and
adhesion films that require various thermal processing.